refactor(fullscreen): route F key through ShortcutsProvider

shortcuts.json already declares fullscreen -> F, but the provider was
listening for KeyF on its own keydown handler in parallel — both fired
on every F press, with the canonical shortcuts dispatch going nowhere.

Subscribe via onShortcut('fullscreen', toggleFullscreen, ...) and drop
the KeyF branch (plus the now-unused inputFocused check). Escape stays
local because its action is gated on the escExitFullscreen profile
setting; F11 stays local because it's shell-only and not in
shortcuts.json.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/common/Fullscreen/FullscreenProvider.tsx

@@ -2,6 +2,7 @@
 
 import React, { useCallback, useEffect, useMemo, useRef, useState } from 'react';
 import { useServices } from 'stremio/services';
+import onShortcut from '../Shortcuts/onShortcut';
 import useShell, { type WindowVisibility } from '../useShell';
 import FullscreenContext, { type FullscreenContextValue } from './FullscreenContext';
 
@@ -56,6 +57,8 @@ const FullscreenProvider = ({ children }: Props) => {
         fullscreen ? exitFullscreen() : requestFullscreen();
     }, [fullscreen, exitFullscreen, requestFullscreen]);
 
+    onShortcut('fullscreen', toggleFullscreen, [toggleFullscreen]);
+
     useEffect(() => {
         if (!core?.active) return;
 
@@ -102,23 +105,10 @@ const FullscreenProvider = ({ children }: Props) => {
         };
 
         const onKeyDown = (event: KeyboardEvent) => {
-            const activeElement = document.activeElement as HTMLElement;
-
-            const inputFocused =
-                activeElement &&
-                (activeElement.tagName === 'INPUT' ||
-                 activeElement.tagName === 'TEXTAREA' ||
-                 activeElement.tagName === 'SELECT' ||
-                 activeElement.isContentEditable);
-
             if (event.code === 'Escape' && escExitFullscreenRef.current) {
                 exitFullscreen();
             }
 
-            if (event.code === 'KeyF' && !inputFocused) {
-                toggleFullscreen();
-            }
-
             if (event.code === 'F11' && shell.active) {
                 toggleFullscreen();
             }